There is known a network game system which includes a plurality of game machines and provides a game played by players that respectively correspond to the plurality of game machines by operating at least one game machine as a server. For example, there is known a network game system which operates any one of 4 game machines as a server-client machine that operates as a server and a client, and operates the other game machines as a client-dedicated machine that operates as a client without operating as a server, thereby realizing a soccer game, a Mahjong game, or the like played by participation of players that respectively correspond to the 4 game machines.
Patent Document 1: JP 2000-342855 A